Anchoring

ABSTRACT

A plastics sleeve for use in holding a bolt in a borehole has a bore having two diameter portions, one wider than the other so that an internal shoulder is formed. A metal thread engaging means, such as a helically coiled spring wire, is inserted in the wider diameter portion to abut the shoulder. The threaded end of the bolt is passed through the narrower diameter portion and rotated to engage the metal thread engaging means. A cap, preferably holding a container of a self-setting mix, is fitted in the mouth of the wider diameter portion and the assembly then inserted in a borehole to rupture the container to release the composition to anchor the sleeve in the hole.

United States Patent Brown 1 July 29, 1975 1 1 ANCHORING 3,589,423 6/1971 Metz 85/32 cs Inventor: J Vincent Brown, n ugh, 3,702,060 11/1972 Cumming 61/45 B England FOREIGN PATENTS OR APPLICATIONS [73] Assignee. Fosmc Switzerland 1,268,624 6/1961 France 85/63 [22] Filed: Primary Examiner-Marion Parsons, Jr.

[2]] Appl. No.: 408,688

Foreign Application Priority Data Oct. 31, 1973 United Kingdom 50176/73 [52] U.S. Cl 61/45 B; 52/698; 85/61; 85/63 [51] Int. Cl E2ld 20/02 [58] Field of Search 85/35, 32 CS, 61, 62, 63; 61/45 B; 52/698 [56] References Cited UNlTED STATES PATENTS 2,022,946 12/1935 Staempfli 85/32 CS 2,570,003 10/1951 Palmer 85/87 2,829,502 4/1958 Dempsey 85/63 3,108,404 10/1963 Lamb 85/63 3,357,730 12/1967 Siler 85/61 Attorney, Agent, or Firm-Caesar, Rivise, Bernstein & Cohen [57] ABSTRACT A plastics sleeve for use in holding a bolt in a borehole has a bore having two diameter portions, one wider than the other so that an internal shoulder is formed. A metal thread engaging means, such as a helically coiled spring wire, is inserted in the wider diameter portion to abut the shoulder. The threaded end of the bolt is passed through the narrower diameter portion and rotated to engage the metal thread engaging means. A cap, preferably holding a container of a selfsetting mix, is fitted in the mouth of the wider diameter portion and the assembly then inserted in a borehole to rupture the container to release the composition to anchor the sleeve in the hole.

6 Claims, 3 Drawing Figures PATENTEU JUL29|975 SHEET ANCHORING' The invention relates to the fixing of a bolt or the like in a bore hole in a substrate, for example. the fixing of an anchor bolt in a hole in a mine gallery roof.

A device for the purpose specified, according to the invention, comprises a generally tubular sleeve. the bore of the sleeve comprising a major diameter portion and a minor diameter portion which, at their union, define a shoulder in the bore intermediate the ends of the sleeve, thread engaging means being located in the major diameter portion in abutment with the shoulder for engagement with the threaded end portion of a bolt received in the sleeve through the minor diameter portion, and a cap closing the mouth of the major diameter portion.

A preferred embodiment of the invention is described with reference to the accompanying drawings in which:

FIG. 1 is a sectional view of the device, a bolt to be anchored and a container holding a self-setting composition;

FIG. 2 is an exploded perspective view of the parts shown in FIG. 1; and

FIG. 3 is a sectional view showing a bolt secured in a hole by the device of FIG. 1.

The assembly of FIGS. 1 and 2 includes a tubular sleeve 1 molded of plastics material such as a polyacetal. DELRlN or a high molecular weight polyethylene. The exterior of the sleeve 1 has longitudinally spaced apart annular ridges 3. A metal collet 4 having peripherally projecting spokes 5 is located in a groove between adjacent ridges at one end, the lower as shown. At the upper end, the mouth of the sleeve is closed by a cap 6 having a lower part 7 which fits closely in the bore 8 of the sleeve 1. The cap 6 has a peripheral wall 9 providing a recess which receives and locates one end of a frangible container 2.

The container 2 holds a self-setting fixing composition. Preferably the composition comprises the interactive ingredients ofa self-setting polyester or epoxy resin mix. where required the interactive ingredients being kept separate from one another while the container remains intact. The material of which the container is made will depend on the nature of the composition; suitable materials for use with a polyester resin mix are unplasticized polyvinyl chloride and acrylonitrile butadiene styrene.

The bore 8 of the sleeve 1 comprises a lower portion 8-a of a relatively minor diameter and an upper portion 8-h of a relatively major diameter so that an annular shoulder 8-(' is formed in the interior wall of the sleeve intermediate its ends. The minor diameter portion 8-a may be about 5 mm less than the major diameter portion 8-b. A tubular metal screw thread forming element 10 fits within the larger diameter portion 8-h of the bore and has one end abutting the shoulder 8-('. This element comprises a length of spring wire coiled into a helix and having screw threads on its interior and exterior surfaces. Such elements are available commercially under the name HELlCOlL." The element 10 is inserted into the sleeve before the cap 6 is placed in position and rotated into engagement with a screw thread formed in the wall of the major diameter portion S-b. After the element 10 is received in the sleeve. a shear pin I1 is passed across the bore through the sleeve. The minor diameter portion 8-a of the sleeve is 'dimensionedsuch that a bolt 12 having a threaded end portion 13 may pass throughthe minor diameter portion to-engagethe element 10:

Toanc hor the bolt 12 in, for example, the roof of a mine gallery, a bore hole 14 (no.3) is made in the roof 15. For a bolt about l6.25"mm in diameter, the hole 14 is preferably about 36 mm in diameter. The bolt is inserted into the open end of the sleeve 1 and threaded into the element 10 until it engages the pin 11, the resistance then encountered indicating that the bolt is fully engaged with the element 10. The container 2 is placed in position on the cap 6 and the assembly is then pushed upward into the bore hole with container 2 leading. The assembly is hammered home to crush the container 2 so releasing its contents and inter-mixing them to form the self-setting mix and also urging the spokes 5 of the collet 4 into engagement with the wall of the bore hole 14. the self-setting mix 16 flows down the annular clearance between the sleeve 1 and the bore hole wall until it reaches the collet 4 which limits egress of the mix from the bore hole. The cap 6 prevents the mix from entering the bore 8 of the sleeve 1. The composition is preferably of a viscosity such that it flows to reach the collet 4 in seconds which means that the operator can then let go of the bolt 12 quickly and move on to the next hole. The bolt may be threaded fully home by applying a torque sufficient to shear the pin 11 and the bolt will then travel home a length dependent on that of the wider diameter portion 8-b generally about 4 or 5 cm.

The pull-out strength of the anchorage formed is enhanced by the shear strength of the engagement of the sleeve 1 with the element 10 and also the compressive strength of the material of the sleeve which lies outwardly of the shoulder 8-c. Because the bolt 12 and the screw thread 10 with which it engages are protected from contact with the set composition, the bolt can be withdrawn whenever desired.

Without further elaboration, the foregoing will so fully illustrate my invention, that others may, by applying current or future knowledge, readily adapt the same for use under various conditions of service.

What is claimed as the invention is:

l. A device for use in the fixing of a bolt or the like in a borehole, comprising a generally tubular sleeve including a bore and formed of a compressible plastic material, said sleeve being adapted to be anchored in the borehole by means of a self-setting composition released into location between the sleeve and the borehole wall, the bore of the sleeve comprising a major portion of a first predetermined diameter and a minor portion of a second, smaller, predetermined diameter, said bore portions forming a shoulder at their junction and intermediate the ends of the sleeve, said minor diameter portion including an open end to receive a threaded end portion of a bolt so that said bolt portion can extend therethrough, thread engaging means located in the major diameter portion and in abutment with the shoulder for engagement with the threaded end portion of the bolt extending through the minor diameter portion, and cap means sealing the major diameter portion of the bore to prevent the ingress of the self-setting mix therein upon its release to thereby preclude contact between said composition and the threaded end of the bolt extending into said major diameter portion.

5. A device according to claim 4 in which the means comprises a frangible pin extending across the bore of the sleeve between the cap of the major diameter portion and the adjacent end of the thread engaging means.

6, A device according to claim 1 in which the cap means is adapted to hold a frangible container of said self-setting composition. 

1. A device for use in the fixing of a bolt or the like in a borehole, comprising a generally tubular sleeve including a bore and formed of a compressible plastic material, said sleeve being adapted to be anchored in the borehole by means of a self-setting composition released into location between the sleeve and the borehole wall, the bore of the sleeve comprising a major portion of a first predetermined diameter and a minor portion of a second, smaller, predetermined diameter, said bore portions forming a shoulder at their junction and intermediate the ends of the sleeve, said minor diameter portion including an open end to receive a threaded end portion of a bolt so that said bolt portion can extend therethrough, thread engaging means located in the major diameter portion and in abutment with the shoulder for engagement with the threaded end portion of the bolt extending through the minor diameter portion, and cap means sealing the major diameter portion of the bore to prevent the ingress of the self-setting mix therein upon its releAse to thereby preclude contact between said composition and the threaded end of the bolt extending into said major diameter portion.
 2. A device according to claim 1 in which the exterior surface of the thread engaging means is in threaded engagement with the sleeve.
 3. A device according to claim 1 in which the thread engaging means comprises a helically coiled metal wire.
 4. A device according to claim 1, including means initially to limit reception of the bolt in the sleeve when a light torque is applied to the bolt and which will yield when the torque is increased.
 5. A device according to claim 4 in which the means comprises a frangible pin extending across the bore of the sleeve between the cap of the major diameter portion and the adjacent end of the thread engaging means.
 6. A device according to claim 1 in which the cap means is adapted to hold a frangible container of said self-setting composition. 